Plasmons are quasiparticles resulting from the quantization of plasma oscillations, just as photons and phonons are quantizations of light and sound waves, respectively. Surface plasmons are those plasmons that are confined to surfaces and that interact strongly with light. They occur at the interface of a vacuum or material with a positive dielectric constant with that of a negative dielectric constant (usually a highly conductive material such as a conductive or doped dielectric).
Plasmonics is a field where one exploits the short wavelength of a surface plasmon in an analogous method as one exploits an optical wavelength for information transfer or data manipulation. But, rather than a quantum of light (a photon), a plasmon or collective excitation in the electron density is used.
Plasmons have also been proposed as a means of high-resolution lithography and microscopy due to their extremely small wavelengths. Both of these applications have seen successful demonstrations in the lab environment. Finally, surface plasmons have the unique capacity to confine light to very small dimensions which could enable many new applications.
Additionally, plasmons have been considered as a means of transmitting information on computer chips, since plasmons can support much higher frequencies (into the 100 THz range, while conventional wires become very lossy in the tens of GHz).
In view of the above, it in an object of the present invention to provide a plasmonic transistor that allows for control of the propagation of surface plasmons. Another object of the present invention is to provide a plasmonic transistor that does not require the surface plasmon to be sustained over a long distance (i.e. on the order of a cm or more). This overcomes the loss requirements because the surface plasmon need only exist over a small region through which it may be switched between two states and subsequently detected. Yet another object of the present invention to provide a plasmonic transistor, wherein the surface plasmon wavelength is shorter than light, so that the effective active area of the device can be smaller than the wavelength of light. Still another object of the present invention is to provide a plasmonic transistor that can be fabricated using existing complementary metal-oxide-semiconductor (CMOS) technology. Another object of the invention is to provide a plasmonic transistor wherein the surface plasmon operational wavelength is close to current industry on-chip interconnect wavelengths.